Pc black screen - won't boot
 

I have a Gigabyte MA790X-UD4DP socket 3 board with AMD Phen II X2 550 cpu, 2 x 2 Gb Kingston ddr2 ram and ATI 4750 1gb card and OcZ modstream power supply, all less than 12mth old. Suddenly went black screen on me and now won't boot up. Won't even get to bios and there are no warning beeps or signs...